Electric valve circuit



May 30, 1939. w. H TEARE ET AL ELECTRIC VALVE CIRCUIT Filed Dec. 29,1937 I t i:

,m w am n r r mg m DW M e 6 Hn W W Wm WWT . of cost.

Patented May 30, 1939 UNITED STATES PATENT OFFICE ELECTRIC VALVE CIRCUITApplication December 29, 1937, Serial No. 182,290

13 Claims. (61. 250-27) Our invention relates to electric valvecircuits, and more particularly to circuits for controlling electricvalve apparatus.

Numerous circuits have been devised for the control of electric valveapparatus. Where the electric valve means is of the type employing anionizable medium, such as a gas or a vapor, and which is providedwith acontrol member which initiates an arc discharge, it has become importantto employ circuits which effect the desired control in a positive andreliable manner and which are not prohibitive from the standpointFurthermore, it is desirable to provide control circuits which areinherently rugged in construction and arrangement and which do notrequire frequent inspection and replacement of parts. In addition, it isfrequently desirable to employ control circuits which generate controlvoltages of predetermined wave form, such as voltages having asubstantially perpendicular wave front which assure positive initiationof arc discharges within the electric valve means.

It is an object of our invention to provide a new and improved electriccontrol circuit.

It is another object of our invention to provide a new and improvedcontrol circuit for electric valve apparatus.

It is a further object of our invention to provide a new and improvedcontrol circuit for electric valve apparatus of the type employing anioniza: ble medium and havinga control member which initiates an arcdischarge between the principal electrodes of the electric valve means.

It is a still further object 01 our invention to provide a new andimproved control or excitation circuit for electric valve apparatus ofthe type employing an'ionizable medium and which includes an anode,a'cathode and a control member in proximity to the cathode whichinitiates an are discharge between the anode and cathode upon theapplication of a predetermined minimum potential across the controlmember and the cathode.

In accordance with the illustrated embodiment of our invention, weprovide an improved control circuit for electric valve apparatus of thetype employing an ionizable medium and which includes an anode, acathode and a control member in proximity to the cathode for initiatingan arc discharge to render the electric valve conductive. The electricvalve means may be of the type requiring the application of a minimumcritical potential across the control member and the cathode toeffectthe initiation of a discharge between the control member and the cathodeand, of

which is charged irom a direct current source.

Means such as a saturable inductive device is employed to establish adischarge between the control member and the cathode and hence to renderthe electric valve conductive. The satura- 10 ble inductive deviceincludes a winding for producing an alternating voltage '0! peaked waveform and this winding is connected in series relation with thecapacitance and the control member. The positive impulses of voltage ofpeaked wave 15 form, acting in conjunction with the voltage produced bythe capacitance, are of suillcient magnitude to render the electricvalve means conductive at a predetermined time during each positivehalf-cycle of applied anode-cathode voltage, or during a predeterminednumber of consecutive positive half cycles. The capacitance, the windingof the saturable inductive device and the control member are connectedin series relation at all times. Suitable phase shifting means areprovided to control the times during the positive halt cycles of appliedanode-cathode voltage at which the electric valve means is renderedconductive.

For a better understanding of our invention, reference may be had to thefollowing description taken in connection with the accompanying drawingand its scope will be pointed out in the appended claims. Fig. 1 or theaccompanying drawing diagrammatically illustrates an embodie mentor ourinvention as applied to at bi-phase rectifier; Fig. 2 represents certainoperating characteristics thereoi, and Fig. 3 diagrammaticallyillustrates an embodiment of our inventipn as applied to an electricwelding circuit. 40

Referring now to Fig. 1 oi the accompanying drawing, we havediagrammatically illustrated our invention as applied to electric valvetranslating apparatus [or transmitting energy from an alternatingcurrent circuit l to a direct current 5 circuit 2 through a transformerI and electric valve means I and I. The electric valve means 4 and 5 arepreiierably of the type employing an ionizable'medium, such as a gas ora vapor, and

:each includes an anode 8, a cathode I and a 50 control member 8. Theelectric valve means 4 and 5 may be or the type employing a controlmember, such as the control member 8, which is in proximity to themercury pool cathode I, and

which requires the application of a minimum critical potentialdifference to initiate an are discharge therebetween. Of course, theestablishment oi an arc discharge between the cathode l and the controlmember 9 initiates a main discharge between the anode 8 and cathode I torender the electric valve means conductive. While for the purpose ofillustrating our invention we have chosen to show it as applied to anelectric valve of this particular type, it is to be understood that ourinvention in its broader aspects applies to electric valve apparatusgenerally.

To energize control members 9 oi electric valve means 4 and 5, weprovide a pair of excitation circuits 9 and I9 which are associated withelectric valves 4 and 5, respectively. The excitation cir ts 9 and IIIare similar in construction and arrangement and in order to facilitatedescription thereof excitation circuit 9 associated with electric valve4 will be considered in particular. The excitation circuit 9 isconnected across cathode I and control member 9 oi the electric valve 4and includes a capacitance Ii which is charged from any suitable directcurrent source II. The capacitance is charged so that the upper platethereof is positive relative to the negative plate. As an agency forproviding a source of unidirectional voltage, we employ any suitablearrangement such as a full wave rectifier l9 including a transformer i4and a pair of unidirectional conducting devices or electric valves l5and ii. The transformer 14 may be energized from any suitable source ofalternating current and in the arrangement illustrated is shown as beingconnected to the alternating current circuit I. As an agency forapplying a voltage of suitable wave form in series relation with thevoltage of capacitance II to establish an arc discharge between cathodel and control member 8, we employ a saturable inductive device H. Thesaturable inductive device ll may comprise a core member i9 having ashunt magnetic path i9 and a restricted saturable path 29. A primarywinding 2| is associated with the core member l9 and a secondary winding22 is associated with the restricted saturabie portion 29 and produces aperiodic or alternating voltage of peaked wave form having asubstantially perpendicular wave front. The secondary winding 22 isconnected in series relation with capacitance II and the control member9 and the voltage generated thereby acts effectively in series relationwith the unidirectional voltage appearing across the terminals ofcapacitance ii. The circuit including capacitance II and secondarywinding 22 is complete at all times and the discharge of the capacitanceH is eflected by the alternating voltage or peaked wave form generatedby winding 221 While for the purpose oi! explaining our invention wehave chosen to show the saturable inductive device I! as the agency forproducing the voltage which eflects discharge oi the capacitance II, itis to be understood that we may employ any other conventionalarrangement for producing a voltage or the required wave shape andmagnitude.

As a means for controlling the time during each positive half cycle ofapplied anode-cathode voltage at which electric valves 4 and 5 arerendered conductive. we provide a circuit 29 which may include atransformer 24 and a suit able phase shifting arrangement such as arotary phase shifter 25. By adjustment of the rotary phase shifter 25,the phase of the voltages impressed on primary windings 2i 0! thesaturable inductive device II is controlled and in this The operation ofthe embodiment of our invention illustrated in Fig. 1 will be explainedby considering the electric valve translating" apparatus when the systemis transmitting unidirectional current to the direct current circuit 2from the alternating current circuit I through transformer I and theelectric valves 4 and 5. As will be well understood by those skilled inthe art, the electric valves 4 and 5 conduct current alternately.Furthermore, it will be understood that the average voltage impressed onthe direct current circuit 2 is maximum when the electric valves 4 and Iare rendered conductive at the beginning of the positive half cycles ofapplied anode-cathode voltage, and that the average impressed on circuit2 decreases as the electric valves are rendered conductive at latertimes during the half cycles. The capacitances II are charged to thepolarity shown by means of the electric valves l5 and II andtransformers II. The rectiiiers I! are designed so that the voltagesappearing across the terminals of capacitances II are insumcient toestablish an arc discharge between cathodes 'l and control members 9. Inother words, the voltage of the capacitances H is less than the minimumvoltage required to break down the auxiliary arc discharge betweencathodes I and control members 9. The saturable inductive device i'lgenerates alternating voltages of peaked wave form in the secondarywindings 22, and these voltages act in series relation with respect tothe voltages produced by capacitances ll. During negative half cycles ofthe alternating voltage produced by secondary windings 22, the netvoltage appearing across cathodes I and control members 9 is of coursereduced so that an arc discharge is not initiated. However, duringpositive half cycles of the voltage of peaked wave form generated by thesecondary windings 22, the voltage generated by these windings is in adirection to increase the voltage produced by capacitance ll so that theresultant voltage appearing across cathodes I and control members Iexceeds the predetermined minimum voltage required to initiate an arcdischarge therebetween. At the predetermined times established by thephase positions oi the voltages oi peaked wave form, the auxiliary arcdischarge paths between cathodes I and control members I are brokendown, eflecting a discharge of the capacitances ll through circuitsincluding secondary windings 22, control members I and cathodes I. 0!course, main arc discharges will be established between the V anodes 9,and cathodes I substantially coincidentaliy with the establishment ofthe auxiliary arc discharges.

The operation of the embodiment ot'our invention shown in Pig. 1 may bebetter understood by referring to the operating characteristics shown inPig. 2. Curve A represents the voltage of the alternating currentcircuit i and may represent the alternating voltage applied to one ofthe electric valves, such as the voltage applied across anode 9 andcathode I of electric valve 4. Curve B represents the voltage which mustbe applied between cathode I and control member 2 to initiate an arcdischarge therebetween. Curve 0 represents the maximum voltage appearingacross the capacitance Ii. Curve D represents the alternating voltage ofpeaked wave form generated by secondary winding 22 of the saturableinductive device I] in circuit 9. Curve E represents the resultantunidirectional voltages impressed on the direct current circuit when aninductive load is connected thereto.

It is to be understood that the voltage of the direct current circuit 2may be controlled by adjustment of the rotary phase shifter 25. When therotary phase shifter 25 is adjusted, the phase relation of thealternating voltages of peaked wave form generated by secondary windings22 is controlled and thereby effects control of the conductivities ofthe electric valves 4 and 5.

In Fig. 3 there is diagrammatically illustrated another embodiment ofour invention as applied to an electric valve system for energizing awelding circuit. The arrangement shown in Fig. 3 is similar in manyrespects to that of Fig. 1 and corresponding elements have been assignedlike reference numerals. The electric valves 4 and 5 eifect energizationof a welding circuit 26 through a transformer 21 having a primarywinding 28 and a secondary winding 29.

As an agency for eflecting energization of the welding circuit 26 at adesired time, we provide a suitable circuit controlling means such as aswitch 30 which permits energization of the control member 8 of electricvalve 4. The switch 30 includes a movable contact SI and stationarycontacts 32 and 33. When the movable contact I engages stationarycontact 32, the capacitance II is charged to the polarity shown from thealternating current circuit I through transformer l4 and electric valvesI5 and i6. When movable contact 3! is in the right-hand position toengage stationary contact 33, the secondary winding 22 of the saturableinductive device H is connected in series relation with the capacitanceII and control member 8 to establish an auxiliary discharge between thecontrol member 8 and cathode 1, thereby rendering the electric valve 4conductive. The resistance 34 is connected in series relation with thecontrol member 8 to control the rate at which the capacitance lldischarges. thereby controlling the interval of time during which thecontrol member 8 is energized, or, in other words. controlling thenumber of halfcycles during which the electric valve 4 is renderedconductive.

In those applications where it ,is desired to transmit alternatingcurrent to the welding or load circuit 26, the electric valve 5 may berendered conductive in response to the current conducted by the electricvalve 4. We employ an alternating current circuit 85 including atransformer 36 having a primary winding 21 and a secondary winding 28for effecting energization of the control member 8 in accordance withthe current conducted by electric valve 4. Primary winding 31 isconnected across primary winding 28 of transformer 21. A switch I! maybe interposed between primary winding 31 and primary winding 2! as ameans to permit selective control of the electric valve 5. so that asubstantially unidirectional current or alternating current may betransmitted to the welding circuit 28. If desired, a suitableunidirectional conducting device 40 may be connected in series relationwith the control member 8 of electric valve I so that onlyunidirectional current is supplied to the control member.

The operation of the embodiment of our invention shown in Fig. 3 issubstantially the same as that explained above in connection with thearrangement of Fig. 1. If the switch 29 is moved to the open circuitposition, electric valve 4 will transmit current to the load or weldingcircuit 28 through transformer 21. Of course, since only one electricvalve is effective under these conditions, energy will be transmitted tocircuit 26 during only half cycles of voltage of a predeterminedpolarity. If the switch 22 is in the closed position, and since theelectric valve I is controlled in response to the current conducted byelectric valve 4, the load circuit 20 will be energized during apositive half-cycle and a following negative half-cycle of voltage ofcircuit I or will be energized during a predetermined number of cyclesof voltage of circuit l.

Referring more particularly to the operation of the control circuitassociated with electric valve 4 when the movable contact 3| of theswitch 30 is in the position shown in the figure, the capacitance llwill be charged to the polarity indicated. When the movable contact 3|is moved to the right-hand position to engage stationary contact 33, thealternating voltage of peaked wave form induced in secondary winding 22,acting in conjunction with the unidirectional voltage of capacitance II,will be sufficient to establish an arc discharge between control member8 and cathode I. This discharge, of course,- will initiate an arcdischarge between anode 6 and cathode 1, thereby rendering the electricvalve conductive. Of course, the load circuit 26 will be energizedduring an interval of time corresponding to the period of conductionofthe electric vaivc 4. If the switch 3! is in the open circuitposition, the electric valve 5 will not be rendered conductive. If theswitch 39 is in the closed circuit position, the electric valve 5 willfollow the electric valve 4 so that the load circuit 28 is energizedduring a complete cycle of the voltage of circuit I. It is to beunderstood that the period of energization of the control member 8 ofelectric valve 4 may be controlled by the design of the circuitincluding the adjustable resistance 34. If the time constant of thecircuit including capacitance ll, secondary winding 22 valve 4 will berendered conductive during only one positive halt-cycle of appliedanode-cathode voltage or during only a portion of one positivehalf-cycle or applied anode-cathode voltage depending upon the settingof the rotary phase shifter 25.. If the resistance 24 is adjusted sothat the time constant of this circuit is relatively large, thedischarge of the capacitance ll may be extended in the direction of thetime axis so that the electric valve 4 is rendered conductive during aninterval of time including more than one positive hali-cycleofanode-cathode voltage, eiiecting energization oi the load circuit 26during a corresponding interval of time. Of course, when it is desiredto eil'ect energizatlon of the load or welding circuit 26 during twohalf-cycles of voltage of circuit Lthe switch 39 may be moved to theclosed circuit position so that electric valves 4 and 5 conduct currentduring a complete cycle. If, for example, it is desired to effectenergization' of the load circuit 26 during four or six cycles, theswitch 88 is maintained in the closed position and the resistance 34 isadjusted so that the discha'rge of the capacitance II is extendedsuiliciently to render the electric valve 4 conductive at the beginningof the proper number of consecutive positive half-cycles of anodecathodevoltage.

tion as applied to a particular system or connections and-as embodyingvarious devices diagrammatically shown, it will be obvious to thoseskilled in the art that changes and modifications may be made withoutdeparting from our invention, and we, therefore, aim in the appendedclaims to cover all such changes and modifications as fall within thetrue spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent oi theUnited States is:

1. In combination, a supply circuit, a load circuit, electrictranslating apparatus connected therebetween and including an electricvalve of the type employing an ionizable medium and having an anode, acathode and a control member for rendering said electric valveconductive, and a circuit connected across said control member and saidcathode for establishing an electric discharge therebetween andcomprising a capacitance, means for charging said capacitance and meansconnected in series relation with said capacitance and said controlmember for producing voltage to eflect discharge 0! said capacltance.

2. In combination, an alternating current sircuit, a load circuit,electric translating apparatus connected therebetween and including anelectric valve of the type employing an ionizable medium and having ananode, a cathode and a control member in proximity to said cathode forinitiating an arc discharge therebetween, and a circuit connected acrosssaid control member and said cathode for energizing said control memberto render said electric valve conductive at a predetermined time duringeach positive half cycle of applied anode-cathode voltage and comprisinga capacitance, means for charging said capacitance and means connectedin series relation with said capacitance and said control member forproducing a periodic voltage oi! peaked wave form for discharging saidcapacitance to initiate an arc discharge between said control member andsaid cathode.

3. In combination, a supply circuit, a load circuit, electrictranslating apparatus connected therebetween and including an electricvalve of the type employing an 7 ionizable medium and having an anode, acathode and a control member for rendering said electric valveconductive. and a circuit connected across said control member and saidcathode for establishing an arc discharge therebetween and comprising acapacitance, means for charging said capacitance and an inductive devicehaving a winding for producing an alternating voltage of peaked waveform for discharging said capacitance to initiate an arc dischargebetween said control member and said cathode, said winding being at alltimes connected in series relation with said capacitance and saidcontrol member.

4. In combination, an alternating current circuit, a load circuit,electric translating apparatus connected therebetween and including aneelctrlc valve oi the type employing an ionizable medium and having ananode, a cathode and a control member in proximity to said cathode forinitiating an arc discharge therebetween, a circuit connected acrosssaid. control member and said cathode for energizing said control memberto render said electric valve conductive at a predetermined time duringeach positive hall cycle of applied anode-cathode voltage and comprisinga capacitance, means for charging said capacitance and means connectedin series relation with said capacitance and said control member forproducing a periodic voltage of peaked wave term for discharging saidcapacitance to initiate an arc discharge between said control member andsaid cathode, and means for controlling the phase oi' said periodicvoltage relative to the voltage of said alternating current circuit. 7

5. In combination, an alternating current circuit, a load circuit,electric translating apparatus connected therebetween and including anelectric valve of the type employing an ionizable medium and having ananode, a cathode and a control member in proximity to said cathode torinitiating an arc discharge therebetween, a circuit connected acrosssaid control member and said cathode tor energizing said control memberto render said electric valve conductive at a predetermined time duringeach positive half cycle of applied anode-cathode voltage and comprisinga capacitance, means for charging said capacitance and a saturableinductive device having a primary winding and a secondary windingconnected in series relation with said capacitance and said controlmember for producing an alternating voltage oi peaked wave term todischarge said capacitance to initiate an arc discharge between saidcontrol member and said cathode, and means for controlling theenergization of said p'rimary winding to control the time during eachpofltive halt cycle of said alternating current circuit at which saidelectric valve is rendered conductive.

6. In combination, a supply circuit, a load circuit, electrictranslating apparatus connected therebetween and including an electricvalve of the type employing an ionizable medium and having an anode, acathode and a control member for rendering said electric valveconductive, and a circuit connected across said control member and saidcathode tor establishing an are discharge therebetween and comprising acapacitance, means for charging said capacitance, means arranged to beconnected in series relation with said capacitance and said controlmember for producing a voltage 01' suflicient magnitude whichcooperating with the voltage of said capacitance is effective todischarge said capacitance through a circuit including said controlmember and said cathode and means for selectively connecting ordisconnecting said capacitance in circuit with said control member.

7. In combination, 'a supply circuit, a load circuit, electrictranslating apparatus connected therebetween and including an electricvalve of the type employing an ionizable medium and having an anode, acathode and a control member for rendering said. electric valveconductive, and a circuit connected across said control member and saidcathode for establishing an are discharge therebetween and comprising acapacitance, means for charging said capacitance, means arranged to beconnected in series relation with said capacitance and said controlmember for producing a voltage of peaked wave form of sufllcientmagnitude to eiiect discharge of said capacitance through a circuitincluding said control member and said cathode and switching means forconnecting said capacitance in circuit with said last mentioned meansand said control member to control the energizatlon oi said loadcircuit.

8. In combination, a supply circuit, a load circuit, electrictranslating apparatus connected therebetween including an electric valvemeans 1| of the type employing an ionizabie medium and having an anode,a cathode and a control mem- F ber for rendering said electric valvemeans conductive, and an excitation circuit connected across saidcontrol member and said cathode for establishing arc dischargestherebetween to render said electric valve means conductive for apredetermined interval of time and comprising a capacitance, means forcharging said capacitance, a resistance, means connected in seriesrelation with said capacitance, said resistance and said control memberfor producing a voltage to eflect discharge of said capacitance througha circuit including said resistance, said control member and saidcathode.

9. In combination, a supply circuit, a load circuit, electrictranslating apparatus connected therebetween and including an electricvalve of the type employing an ionizable medium and having an anode, acathode and a control member for rendering said electric valveconductive, a control circuit connected across said control member andsaid cathode for establishing arc discharges therebetween and comprisingacapacitance, means for producing a periodic voltage of peaked waveform, means for charging said capacitance and means for selectivelyconnecting said capacitance to said last mentioned means or to saidcontrol circuit to control the energization of said load circuit, andmeans for controlling the rate 01' discharge of said capacitance tocontrol the period of energization of said load circuit.

10. In combination, a supply circuit, a load circuit, electrictranslating apparatus connected therebetween and including an electricvalve of the type employing an ionizable medium and having an anode, acathode and a control member for rendering said electric valveconductive, a control circuit connected across said control member andsaid cathode for establishing arc discharges therebetween and comprisinga capacitance, means for producing a periodic voltage of peaked waveterm, means for charging said capacitance and means for selectivelyconnecting said capacitance to said last mentioned means so that thevoltage of said capacitance and said periodic voltage act eflectively inseries to discharge said capacitance through a circuit including saidcontrol member and said cathode to render said electric valveconductive, and means for controlling the rate or discharge of saidcapacitance to control the period of energiaation 01' said load circuit.

11. In combination. a supply circuit, a load circuit. electrictranslating apparatus connected therebetween and including an electricvalve of the type employing an ionizabie medium and having an anode, acathode and a control member for rendering said electric valveconductive, and a control circuit connected, across said control memberand said cathode for rendering said electric valve conductive tor apredetermined portion of a single positive halt cycle of appliedanodecathode voltage and comprising a capacitance, means for chargingsaid capacitance, means for producing a voltage of peaked wave formwhich acting in conjunction with the voltage of said capacitanceestablishes an arc discharge between said cathode and said controlmember and means for connecting said capacitance in series relation withsaid last mentioned means and said control member to render saidelectric valve conductive.

12. In combination, a supply circuit, a load circuit, electrictranslating apparatus connected therebetween and including an electricvalve of the type employing an ionizable medium and having an anode. acathode and a control memher for rendering the electric valveconductive, a control circuit connected across said control member andsaid cathode for rendering said electric valve conductive for apredetermined interval of time and comprising a capacitance, means forsaid capacitance and means for producing a periodic voltage of peakedwave form which acting in conjunction with the voltage 0! saidcapacitance discharges said capacitance to establish an arc dischargebetween said cathode and said control member, and means for controllingthe rate of discharge 01' said capacitance to render said electric valveconductive ima predetermined number of consecutive positive halt-cyclesof applied anode-cathode voltage.

13. In combination, an alternating current supply circuit, a loadcircuit, electric translating apparatus connected therebetween andincluding an electric valve or the type employing an ionizabl medium andhaving an anode, a cathode a control member for rendering said electricvalve conductive, and a circuit connected across said control member andsaid cathode tor establishing an arc discharge therebetween andcomprising a capacitance, a rectifier energized from said alternatingcurrent supply circuit for charging said capacitance and means connectedin series relation with said capacitance and said,

control member for producing a voltage to efl'ect discharge of saidcapacitance.

WILLIAM a. man. 01mm w. uvmas'ron.

CERTIFICATE OF CORRECTION. Patent No. 2,160,688. May 0, 19 9.

WILLIAM H. TEARE, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correctionss follows: Page 1,secand column, line 36, for the Word. "et read a; page 2, first column,line 21, strike out "the"; same page, second column, line 19, after"average" insert voltage; and that the said Letters Patent shouliiberead with this correction therein that the same may conform to therecord of the case in the Patent Office.

Signed and sealed this 18th day of July, A. D. 1939.

Henry Van Aredsle (Seal) Acting Commissioner of Patents.

